Summaries of ASTM standards

• Length x Width x Depth - 200 mm x 75 mm x Thickness of Sandwich Construction

• Make sure to test at least five specimens per test condition.

• Apparatus: Universal Testing Machine (UTM)

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Figure 1: Universal Testing Machine (UTM)

1. Condition the specimen in a chamber if the test environment is not the same as a conditioned environment.

2. Measure the length, width and thickness at three places in the specimen.

3. Place the specimen into the test fixture as shown in the equipment and apparatus section.

4. Attach the deflection transducer (if we choose to use one).

5. Apply a compressive force to the specimen until failure or until a deflection equal to the thickness is reached.

• 3-point or 4-point bend test

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Figure 3: 3-Point Bend Test

Figure 4: 4-Point Bend Test

• Force versus crosshead displacement, force versus deflection data continuously, or at frequent intervals (around 2-3 recordings per second, with a target minimum of 100 recorded data points)

• If there are any initial failures, record force, displacement and mode of damage where the failure occurs. 

• Record mode, area and location of each failure. 

• Use the failure identification codes, shown in the figure below.

• Record the max force, failure force, head displacement and the deflection at the moment of ultimate failure. 

• For ultimate failure modes, record the mode, area and location of ultimate failure for each material. 

• Calculations:

  • For 3-Point Mid-Span Loading:

  • For 4-Point, Quarter-point loading:

  • For 4-Point (Third Point) Loading: